An example of fuel injection valve using a known technique is disclosed in Japanese Unexamined Patent Publication No. 2003-336562. In the technique, atomization of fuel injected from plural fuel injection orifices is promoted making use of a swirling fuel flow.
The fuel injection valve has a valve seat member in which a downstream end of a valve seat cooperating with a valve element has opening formed through the front end surface of the valve seat member and an injector plate joined to the front end surface of the valve seat member. Between the valve seat member and the injector plate, lateral paths and swirling chambers are formed. The lateral paths communicate with the downstream end of the valve seat. The downstream ends of the lateral paths are communicated with the swirling chambers in the tangential directions of the swirling chambers. The injector plate has fuel injection orifices formed therethrough for injecting fuel swirled in the swirling chambers. Each of the fuel injection orifices is shifted by a predetermined distance from the center of the associated swirling chamber toward the upstream end side of the associated lateral path.
The structure described above can effectively promote atomization of fuel injected from each fuel injection orifice.
The fuel injection valve described in Japanese Translation of PCT International Application Publication No. 2000-508739 has a valve seat member including a stationary valve seat, a valve closing member which cooperates with the valve seat member and which can move along the longitudinal axis of the valve, and a circular plate which includes a hole and which is disposed downstream of the valve seat. The circular plate having a hole has at least one flow-in area and at least one flow-out opening. The upper functional plane having at least one flow-in area differs in opening geometry in a cross-sectional view from the lower functional plane having at least one flow-out opening. In the fuel injection valve, the lower end surface of the valve seat member partly and directly covers at least one flow-in area of the circular plate causing at least two flow-out openings to be covered by the valve seat member.
In the structure described above, S-shaped drifting is realized in the fuel flow for fuel atomization improvement, so that a highly-atomized fuel spray shape is obtained.